DMC - History - Greenland really was green, world's oldest DNA reveals

July 7, 2007

A depiction of "green" Greenland

THE oldest DNA found on earth has been collected from under a kilometre of ice in Greenland, revealing that the frozen island really was once green.

Half a million years ago Greenland was covered by lush forests filled with butterflies, moths and the ancestors of beetles, flies and spiders. The finding has implications for global warming, suggesting the Greenland ice sheet, which holds enough water to raise sea levels by seven metres, might not melt as quickly as thought.

A Danish-led team, including the Australian researcher Michael Bunce, extracted the ancient DNA from the muddy bottoms of cores drilled deep into the ice cap in southern Greenland. The researchers identified genetic traces of a surprising variety of tree species, including spruce, pine and yew. The team believes the DNA is between 450,000 and 800,000 years old, based on their analysis of insect genetic material.

Dr Bunce, of Murdoch University, said it was a fascinating new way to study the past. "Preserved DNA from plants, animals, insects and bacteria that died hundreds of thousands of years ago can aid in our understanding of how the earth's environment has changed," he said.

Researcher Eske Willerslev said: "We have shown for the first time that southern Greenland, which is currently hidden under more than two kilometres of ice, was once very different to the Greenland [of] today."

The discovery of ancient DNA from a warm period half a million years ago suggests that ice on top of the ancient forest did not melt as believed during the last warm period, 116,000 to 130,000 years ago, when temperatures were 5 degrees higher than today. If it had, the remains of the ancient trees and insects would have been replaced by new flora and fauna.

"If our data is correct, this means that the southern Greenland ice cap is more stable than previously thought," said Professor Willerslev, whose team's findings are published today in the journal Science.

This did not mean sea levels would rise more slowly than predicted, he warned. The five- to six-metre rises during the last warm period must have come from sources other than Greenland, such as Antarctica, he said. "As the earth warms from man-made climate change, these sources would still contribute to a rise in sea levels."

Erik the Red, who settled in Greenland 1000 years ago, named it to lure more settlers, although a small area not covered by ice would then have been very green.